The deific decree doctrine allows criminal defendants who believe that God commanded them to kill to plead not guilty by reason of insanity to murder. The insanity defense has remained moored to its Judeo-Christian roots, which has artificially limited its bounds. While civil law has focused on individualism within religion, criminal law has imposed state-defined limits on what religion (or socially acceptable religion) is. This Article argues that the deific decree doctrine is too closely tied to artificial limits on insanity imposed by 19th century developments in the mental health profession and criminal law. The doctrine unacceptably privileges certain mentally ill criminal defendants whose delusions fit within an outdated model that is not psychiatrically valid. Moreover, it has disparate gender consequences that harm women with postpartum psychosis who kill their children while supporting men who kill their female partners. The Article concludes by calling for the end of the deific decree doctrine and expanding the insanity defense so it more accurately tracks psychiatric understanding of mental illness.